Bearing system

ABSTRACT

A bearing arrangement at the intake aperture of a centrifugal pump impeller in which a bearing shell (5) arranged in the housing (4) can be fitted from outside the pump. The bearing shell (5) is positioned by a retainer (7) and the flange (10) of a pipe to be connected thereto.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a bearing system for centrifugal or rotarypumps, consisting of a bearing seat or shell situated within the pumphousing and of a centrifugal-pump impeller pivoting within the bearingshell on the intake port.

2. Discussion of the Related Art

A bearing system is described in GB-PS 805 825. There, the bearing shellof a hydrostatic bearing is pressed into the pump housing, and animpeller having an elongated suction or intake port extends into, andpivots in, the shell. This is a complex and costly design in that itrequires very precise machining of the inside of the housing in order toprevent misalignment in the assembly stage. A somewhat similar design isshown in DE-OS 30 11 380 in which a double-suction impeller, with bothof its intake ports, is supported directly within corresponding bearingshells.

The intake port may be designed to also serve as the rotor of anelectric motor as has been described in GB-PS 909 550.

SUMMARY OF THE INVENTION

This invention is aimed at providing for centrifugal pumps in thisgeneral design category a bearing system that is easy to install and canbe controlled with a minimum of effort and cost. The solution to theproblem includes a bearing shell disposed within the pump housing of acentrifugal pump. A retaining unit, which may be manipulated from theoutside, holds the bearing shell in position within the housing. Thepresent invention permits the machining of the surfaces accepting thebearing-shell, and also permits the installation of the bearing shellitself, from the outside of the pump housing. Apart from easieraccessibility, this translates into a substantially reduced machiningprocess. It also permits easy checking of the condition of the bearingby simply disconnecting the attached pipe such as a suction pipe. In thepast this inevitably involved a disassembly of the pump which has nowbecome altogether unnecessary. The subclaims describe Additionalenhancements and advantageous design features of this invention include,for example, that the contact surfaces between the retaining unit andthe flange and housing, respectively, can be sealed by means ofwell-established methods using for instance O-rings, flat gaskets or thelike. The type of seals and gaskets to be selected is determined by thenature of the operating conditions of the pump. Anti-twist lockingelements prevent any possible rotation of the bearing shell. Tocompensate for dimensional tolerances in manufacturing and for shaftdeflection and to attentuate vibration of the rotating unit, the bearingshell is mounted in tiltable fashion. By way of example, this can beaccomplished by means of a narrow, outward rim or collar by which thebearing shell is kept centered in the housing. The bearing shell or thecollar may be provided with two lugs or stubs which, while permitting atilting movement, assure support of the bearing shell on the retainingunit. This configuration is useful in the case of pumps with highinternal pressure levels which might attain magnitudes in excess of thelevel that car, be handled by an elastic tilt mount.

If there is wear and tear on the bearing shell, the design of thebearing system is such as to permit easy replacement. The shortestphysical length of a pump is attained when the flange of a pipe conduitconnected to the pump bears directly on a retaining unit. In thisextremely simple fashion, the flange bolts, via the retaining unit,serve to fasten the pump bearing inside the housing. This approach isequally suitable for single-stage and multi-stage centrifugal pumps. Abearing system based on this design permits both a reduction of theoverall physical length of the pump and a substantial improvement in therigidity of the rotating assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

A design example of this invention is illustrated in the diagrams andexplained in more detail in the following description.

FIG. 1 shows a cross section of the first impeller of a pump;

FIG. 2 shows a section along the horizontal plane of a pump operating ata higher pressure level;

FIG. 3 is an enlarged representation of a detail in FIG. 2; and

FIGS. 4 and 5 are, respectively, an enlarged representation of a sideview and a top view of a stub.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

FIG. 1 shows an impeller 1 of a single-stage centrifugal pump, or thefirst impeller of a multi-stage centrifugal pump, fastened to a shaft 3by means of a screw 2. A bearing shell 5 is inserted from the outsideinto the housing 4 and is supported in tiltable fashion with its narrowcollar 15 positioned between elastic gasket rings 6. A retaining unit 7,likewise installable from the outside, holds the bearing shell 5 inplace. In terms of functionality, the retaining unit 7 is in this casedesigned as a thrust collar. A gasket 8 seals the retaining unit 7 offagainst the housing 4 while a gasket 9 seals it against the flange 10 ofa pipe conduit that feeds the medium to the pump. Conventional fasteningmeans, bolts 11 in this example, tightly hold the flange 10 against thehousing 4 and, in the process, press the retaining unit 7 and theabutting bearing shell 5 into the housing 4. An anti-twist lock 12prevents any rotation of the bearing shell 5. At the intake port 13, theimpeller is provided with a race 14 which slides inside the bearingshell 5.

For applications involving very high pressure levels in the lateralspace around the impeller 1, FIG. 2 shows a solution whereby two axiallyprotruding stubs 16 are provided in the horizontal plane of the rings onthe collar 15. The sectional view shown here corresponds to a horizontalcross section through the intake side of a pump. The force of thepressure on the intake side of the lateral space around the impellercauses the bearing shell 5 to be pushed forward against the direction ofthe medium feed flow and to be braced by the retaining unit 7. The twolugs or stubs 16 protruding horizontally ensure the possibility of atilting movement in the event of a shaft deflection. In lieu of the twoelastic gasket rings 6 only one single gasket ring 6 is used in thisdesign.

FIG. 3 is an enlarged representation of the detail within the circle inFIG. 2. In the example shown here, the collar 15 is provided with twostubs 16 extending in the horizontal plane at diametrically oppositeends. These stubs are in direct contact with the retaining unit 7 andtransfer to it those axial pressures which, as a function of thepressure level in the lateral space around the impeller on the intakeside, bear on the exposed front face of the bearing shell 5. The contactarea of the stubs 16 is so designed and dimensioned that the maximumpermissible surface pressure is not exceeded while at the same time thetilting motion around the two stubs 16 is assured.

FIG. 4 shows an enlarged side view of one stub 16 on the collar 15 whileFIG. 5 is a frontal view of a bearing shell 5 incorporating suchprotruding stubs 16. These stubs may be produced for instance by amachining, pressure-bonding, casting or any other conventionalmechanical process.

This type of impeller or shaft bearing arrangement permits easiestpossible access to the bearing for inspection and verification purposes.By simply removing the pipe conduit, here shown in the form of a suctionpipe, one can instantly inspect the bearing and, if damaged, replace itin short order. Complete disassembly of the pump, a common practice inthe past, is no longer necessary. The operator of a centrifugal pumpdesigned according to this invention is thus able not only to inspectand, if necessary, repair the unit without any difficulty but alsobenefits from a mere minimum of production downtime. Moreover, thisconcept lends itself to a substantial reduction in the physical lengthof the pump. This is important considering that the widely used designin which the shaft bearing pivots in a bearing support located withinthe inlet cross section can quite negatively affect both the vibrationalproperties and the physical length requirements.

I claim:
 1. A bearing arrangement for a centrifugal pump comprising:apump housing; an impeller rotatably mounted within said pump housing,said impeller including an intake port; a beating shell pivotablymounted within the pump housing about the intake port, wherein aretaining unit, which may be manipulated from outside the pump housingholds the beating shell in position within the pump housing.
 2. Abearing arrangement as in claim 1, wherein the retaining unit is sealedagainst the pump housing and a flange.
 3. A bearing arrangement as inclaim 1 wherein the pump housing or the retaining unit is provided withat least one anti-twist locking element connected to the beating shellto prevent rotation of the beating shell.
 4. A bearing arrangement as inclaim 1, wherein the beating shell is so mounted as to permit a removalthereof for replacement.
 5. A beating arrangement as in claim 4,wherein, by means of a radially protruding collar positioned betweenelastic tings, the bearing shell is mounted in a manner permitting thepivoting motion.
 6. A beating arrangement as in claim 4, wherein thebeating shell protrudes in the axial direction with at least twocoplanar stubs.
 7. A bearing arrangement as in claim 6, wherein thestubs butt against the retaining unit.
 8. A bearing arrangement as inclaim 1, wherein a flange of a feeder pipe connected to the pump pressesthe retaining unit against the bearing shell.